In clinical electro-physiology there is a growing interest for multisite cardiac pacing intended to be used for prevention and/or therapy of such pathologies as Atrial Fibrillation (AF) and dilative cardio myopathy (DCM).
It has been proven that appropriately timed (sequential and/or simultaneous) somministration of electrical therapy to the different cardiac chambers, up to all four of them, Right Atrium (RA) and Right Ventriculum (RV) and respectively Left Atrium (LA) and Left Ventriculum (LV) can be beneficial to the patients. The appropriate timing of the stimuli shall be chosen according to the appropriate therapy, but it is crucial, to perform such task, that an adequate number of suitable electrical connections be made to every and each heart chamber to be paced and/or defibrillated.
In particular, the above said pathologies are, nowadays, considered as the most likely to experience beneficial effects from multi-site pacing, for said reason the following description will be focused on the above said category of cardiac patients, said particularization not being detrimental to the purpose of disclosure of the general principles underlying the present invention.
Atrial fibrillation (AF) is a fairly common disease, manifesting as a chaotic acceleration of atrial rhythm, comporting loss of atrial and contraction efficacy.
A number of methods have been used to revert such rhythm to sinusal rate (cardioversion), the most used being infusion of anti-arrhythmic drugs and/or electrical cardioversion in a sedate and de-coagulated state.
Such methods, however, cannot control recurrence of AF episodes, while implant of an atrial defibrillator has, as a consequence, highly painful, non tolerable, electrical shock administered to the conscious patient. Implant of a pacemaker featuring multi-site stimulation has therefore been experimented.
DCM, on the other side is a severe illness comporting ventricular life-threatening arrhythmias and contractile cardiac deficiency. The outcome of such pathology being cardiac transplant. Multi-site electrical pacing is used in this pathology as well, aiming to re-synchronization of ventricular contraction.
In order to achieve a multi-site cardiac stimulation it is nowadays mandatory to place an appropriate number (three or more) electro-catheters in the targeted cardiac cavities. Such practice being detrimental to the patient""s and operator""s safety because of prolonged exposure to x-rays and other possible risks, this not considering the high rate of lead dislodgement and lack of reliability of such a complex wiring system.
The purpose of the present invention is to propose a solution to the problem of multi-site pacing to be less aggressive and more reliable, so to represent a possible alternative even in the general single chamber pacing therapy.
Targeting the said purpose we previously submitted an Italian patent request, number FI/98/A/223, in which we describe an electro-catheter featuring a double spiral pre-formation, to be located in proximity of the atrial chambers and respectively the ventricular chambers, through the coronary sinus.
This invention relates to a method of introducing one or two separate electro-catheter leads in the coronary sinus (CS), such leads being supported by a purpose made structure, similar in shape and function to a coronary xe2x80x9cstentingxe2x80x9d device. Once introduced and properly placed in the vessel the xe2x80x9cstentxe2x80x9d structure, bearing the pacing leads, will be expanded in the vessel, thus forcing the stimulating electrodes against the walls of the same.
The most important feature of said electro-catheter system is that it is conceived to be placed in the coronary sinus (CS), thanks to the anatomical characteristics of this vessel. The CS, in fact, is a venous vessel almost cylindrical in shape, whose average diameter in the human is estimated at 15 millimeters and whose length is approximately 30-40 millimeters.
The CS drains most of the venous blood returning from the heart muscle: it is a large vein opening in the right atrium and collects the blood from several smaller veins from different areas of the cardiac walls.
The position in the heart of the CS is basic to the described invention. The coronary sinus path, in fact, starting from its ostium in the right atrium, follows a route along the posterior atrio-ventricular groove, then it follows the groove in its lateral portion, ending its course in the inter-ventricular anterior groove, in the area that separates the two ventricles.
For this reason the CS is characterized by the fact to be in contact, along its antero-superior portion with the posterior wall of the right Atrium, and, after approximately 15-20 mm from the OSTIUM it is in contact with the posterior wall of the Left atrium.
The infero-anterior portion of the CS, in its first portion, is in contact with the posterior wall of the Right Ventricle, while the second portion is in contact with the posterior wall of the left Ventricle, as can be observed in the diagram in FIG. 1.
Said configuration makes it possible to stimulate each and every of the four cardiac chamber through a catheter placed in the CS.
Stability of the lead, pacing reliability, and low stimulation threshold, however, cannot be achieved by use of a standard linear electro-catheter of the type in common use with implantable cardiac pacemakers. The contact of such lead to the aimed walls, in fact, would not be stable, due to the large dimensions of the CS in comparison with the catheter diameter.
The present invention, therefore, is targeted to solve this problem.